If your answer to any of the previous questions was anything above “Yeah, I guess,” then you might want to check out publisher Chillingo’s puzzle offering, The Impossible Line. It’s out now, it works on your iPhone or iPad, and it does one thing really well: make you swear at a tiny triangle.

I sound a little glib up there, but the truth is that The Impossible Line is actually pretty fun. It’s a puzzle game that takes place on a chalkboard, and the goal is to drag a plucky triangle into its home in a cozy-looking circle. And you have to do this without the triangle touching the edge of the board or one of the drawn-on obstacles between it and its goal.

Oh, also? The obstacles become invisible after a few seconds, and you have to find your way around them from memory with only a vague radar system to guide you. If this sounds evil, that’s because it kind of is. But once you get past the unfairness of it all, The Impossible Line proves surprisingly addictive. And it’s way more satisfying than it should be when you pull off an especially tricky maneuver.

Stay on target …

It really helps that you don’t have to actually touch the triangle to move it; you can drag anywhere on the screen, and the brave little wedge will follow your movements. This clears up your view for some of the more precise maneuvers you have to pull off later on.

Completing levels earns you coins you use to buy one of two helpful power-ups. One gives you another quick peek at the orientation of the obstacles, and the other puts a “lamp” on the pointer so you can kinda-sorta see where the walls are.

It’s the kind of game where you’ll set out to play one level and do a dozen instead.

While the core gameplay is quick, simple, and catchy, a couple nagging problems drag the experience down. I had a few hard locks during my time with it and had to restart. It’s a pretty big issue in a title that requires as much concentration as this one does at times.

The in-game ads are also annoying. Between levels, they take up most of the bottom of the screen and the entire upper-right corner. This doesn’t happen during levels, but every once in a while you’ll have to play a “What do I have to touch to close this thing?” minigame to get past a full-screen ad standing between you and the next puzzle. This is the price of free games, of course, and you can pay $1.99 to remove them if it gets to be too much. It’s almost like they planned it.

Overall, however, The Impossible Line is a deceptively fun time. It’s the kind of game where you’ll set out to play one level and do a dozen instead. And the price is right, provided you don’t mind all the ads.

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Game Name: The Impossible LineThe Good: It’s quick, simple, surprisingly hard to put down, and some levels make you feel like some kind of genius when you complete them.The Bad: Occasional freezes and annoying ads.The Verdict Dragging a triangle past invisible barriers onto a circle probably shouldn’t be fun, but it really is.Buy from:App Store